We then repeated the infection of THP-1 cells with 2 PFU/cell and measured the induction of CXCL10 and IFN-β mRNA by quantitative PCR at 24 h p.i. MVA infection triggered CXCL10 expression, whereas COP and WR infections did not (Fig. 1C). This evidence concerns the gene IFNB1 and infection.